Biasing transistors VS lowering the voltage on the transistor

[vincediamond]

What is this called when your power supply voltage is not biasing the transistor right? because the voltage is so low?

What does it do to the transistor when the voltage is so so low? and what is this called when u do this to a transistor?

When i turn down the voltage very low on my fuzz face it sounds different VS using biasing trimmers to try to mimic it why is that?

Example:

Fuzz face is at 9 volts power supply, adjusting the biasing trimmer will kinda of sound like the fuzz face is at 3volts or 1 volt but its different when you turn down the power supply voltage to 2 volts and set the biasing trimmers at (operating points) it will unbias the transistor from the power supply voltage

The biasing trimmers can put different voltages on the base,emitter,collector , and feedback resistor. This can make the transistor sound very unbiased.

But what is the biasing trimmers doing to the transistor really? it makes it breakdown,distort different and can make it sound harsh,changing the attack, and decay of the fuzz why is that?

Lowering the power supply voltage of the fuzz face can also change the sound , changing the attack,decay,breaking it down,distorting different but why? what is it doing to the transistor??

[52 Bill]

I don't know how you are "biasing" your transistors with a trimpot, but changing the proportion of voltages applied to the terminals of a transistor will not be the same as changing the overall voltage level to a transistor circuit.

Biasing a transistor is done to set its operating point so that it is either turned on or off, so that it will react to an applied signal in a controlled manner.

Due to the lack of quality germanium transistors, most boutique Fuzz Face designs use trim pots to adjust the circuit to the available transistor.

Changing the voltage applied to the circuit will not generally alter the proportion of voltages applied to the individual transistors.

[vincediamond]

Thanks for the help

1) Changing the proportion of voltages applied to the terminals of a transistor will not be the same as changing the overall voltage level to a transistor circuit.

Why is that ? Whats the difference about it?

2.) Changing the proportion of voltages applied to the ternimals Base,emitter,collector of the transistor will do what to the transistor in a fuzz circuit?

3.) changing the overall voltage of the circuit will do what to a transistor?

[52 Bill]

Let me start by saying that all of my numbers here are totally random, and have been picked to illustrate the concept.

If you change the circuit design to apply different voltages to the base, emitter, and collector of a transistor (biasing), you set how the it operates, when it turns on or off or how much gain the stage will have, etc. This will be different for different transistor types. And in the case of germanium transistors, this may be different for individual transistors of the same type.

When you change the voltage going to the circuit it may change the sound, but not in the same way. Let's say a transistor is running at 10 volts. If you increase the voltage to the circuit and you increase it past the breakdown voltage of the transistor it will burn out. If you reduce the voltage to say 6 volts the transistor will still operate, and may sound fine, but the overall ability of the transistor to handle different signals and loads will change. Let's say now instead of being able to handle an 8 volt signal before distorting, it will only handle a 4 volt signal.

It's kind like using the volume control versus the balance control on your stereo.

[vincediamond]

If you change the circuit design to apply different voltages to the base, emitter, and collector of a transistor (biasing), you set how the it operates, when it turns on or off or how much gain the stage will have.


Yes the Biasing sets the operating voltages and Gain , plus the "symmetry" of the positive and negative cycles

The Fuzz face symmetry is clipping, different waveshape envelope which is based on the resistor values of the biasing

If you change the biasing resistor values this will change the clipping,symmetry,gain,operating voltages,waveshape

If you change the "overall voltage" of the circuit applied this also changes the "headroom limits" of the clipping,symmetry,gain,operating voltages,waveshape

If you put 1 ot 2 volts on a fuzz face it still works, the transistors are in the ON state but they sound like they are barely working , it sounds like a dieing battery sound.

When transistors make that dieing battery sound what kind of operation or stae is the transistor in?

It seems like the transistor is trying to work "below" the operating voltages but what happens when you do this to the transistor?

It has different distortion fuzz characterists VS changing the biasing operating voltages but why?

[52 Bill]

I really don't know how to answer your question.

A transistor needs less than a volt on its base in order to turn on, but at low supply voltages it will not be running in its linear area of operation.

Perhaps someone versed in the field of physics can better answer your question.

[vincediamond]

1.) At low supply voltages it will "not" be running in its linear area of operation.

why is that?

What kind of area of operation will the transistor be running in?

[R.G.]

1.) At low supply voltages it will "not" be running in its linear area of operation.
why is that? What kind of area of operation will the transistor be running in?

Go read "How it works" at GEO.

Edit:
I didn't realize at first - vincediamond is our old friend walters/markphaser.

I hope someone else can use the info in the url I posted.

[vincediamond]

i just read RG info it has nothing to do with my questions i asked

It says nothing about silicon and germanium operations at very lower voltages and what happens , nothing about the different between under or over biasing the transistor between a silicon vs a germanium , whats the difference distortion qualities about silicon vs germanium

[Alex R]

What kind of area of operation will the transistor be running in?

Curved.

[vincediamond]

If the transistor's operation is running in "curved" what does that mean Vs linear operation?

[Alex R]

Just my little joke. But operating curves are published for transistors, so you can see where operation cuts in as voltage rises etc etc. 'Linear' means on a straight portion of the curve, where operation is predictable. Usually it means 'responding to all audible frequencies in a similar way', but it always means what it says and it can apply to any type of curve. Take a look at the curves for the devices you're using.

When transistors are on the edge of operation you might get a kind of quantum effect where only a few electrons are moving. Things get more unpredictable, and the sound can be 'gritty'. I guess that's what you're talking about. I should think different devices would respond in very different and not very predictable ways. 'How it works' at GEO does in fact specifically answer these questions in the only possible way - by giving you the theory behind the issue. I got the ideas above about 'grittiness' from it, I seem to recall. Take another look, you're missing something, it's good information. And it's in sentences.

[vincediamond]

yes when the transistor is at very low voltage it creates a grittiness.

The silicon transistor BC108 has a different grittiness at very low voltage VS the germanium NTK275

Whats the difference between the grittiness from germanium and silicon?

My electronic books mostly just talk about the linear operation biasing. The books don't talk much about what happens when you underbias or over bias the transistor and what is happening to the transistor. The books also don't talk much about when you lower the overall voltage way below the operating levels

I set my germanium fuzz face NTK275 at 1volt power supply and my silicon fuzz face BC108 at 1 volt power supply also. They both sound different, causing different breaking up sounds and grittiness sounds.

What is happening to the transistor when appling very lower voltage to it?

What is the called when you do something like this to the transistor?

[R.G.]

Take another look, you're missing something, it's good information. And it's in sentences.

Alex - In his previous appearances, walters/markphaser has been or acted unable to read and comprehend any reference materials. Had I realized who it was, I would not have put in the pointer to my stuff. He either cannot or will not read and comprehend.

[vincediamond]

How can anyone comprehend when the right information is not even there in the first place

The answers are clearly not in that hyperlink to my questions so there is nothing to comprehend

Maybe RG needs to re-read it or re-write it to make it more clear so people can comprehend it better why keep it so hidden and secret RG?

Don't think this RG guy is very smart cause he has magical secrets, most of the information is stolen from electronic books,teachers in his past, and bad relationships he has stolen from people online which i'm now finding out from emails and networking

R.G likes to play humpty dumpty games its just pure lyes making him appear smarter than what he really is. Don't believe everything you hear from this guy R.G take it with a grain of salt ,its not him that made it up he has stolen it from others trust me he has made his marks through his past.

If you got the answers RG just "spell it out" then why keep it secret